package week10;

import java.util.Scanner;

public class PTA7_1 {

	public static void main(String[] args) {
		Scanner in=new Scanner(System.in);
		int []a=new int [5];
		String str=in.next();
		while(!str.equals("exit")) {
			try {
				if(str.equals("arr")) {
				int n=in.nextInt();
				int m=a[n];
				}
				else if(str.equals("null")) {
					System.out.println("java.lang.NullPointerException");
				}
				else if(str.equals("cast")) {
					Object x=new String("a");
					System.out.println((Integer)x);
				}
				else if(str.equals("num")) {
					String str2=in.next();
					int i=Integer.parseInt(str2);
				}
				else 
					return ;
			}catch(Exception e) {
				System.out.println(e);
			}
			str=in.next();
		}
			
	}

}
